EVAP Canister
WARNING:
DO NOT try to suck air through EVAP canister. Fuel vapors inside canister are extremely harmful.
Remove hoses from EVAP canister. Locate port on canister that goes to fuel tank and blow air into it. There should be no restriction of air flow through canister PURGE pipe and AIR pipe. Plug PURGE and AIR pipes and try to blow into TANK port again. If able to blow air into TANK port, canister is leaking and must be replaced.